[media] vivid: don't use more than 1024 bytes of stack

Remove the following compilation warnings:

	drivers/media/platform/vivid/vivid-tpg.c: In function 'tpg_gen_text':
	drivers/media/platform/vivid/vivid-tpg.c:1562:1: warning: the frame size of 1308 bytes is larger than 1024 bytes [-Wframe-larger-than=]
	 }
	 ^

This seems to be due to some bad optimization done by gcc.

Moving the for() loop to happen inside the macro solves the
issue.

While here, fix CodingStyle at the switch().

Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>